Cell culture (mammalian cell culture) procedures using a bioreactor or fermentation (microbial cell culture) procedures using a fermentor or fermentation vessel embody techniques for growing and proliferating unit cells separate from an organism and is widely used in biology, medical science, pharmacy, and agriculture. Additionally, the use of biological cultivation procedures has expanded into other disciplines, such as the treatment of waste water or oil.
Apparatuses designed for cultivation of microbial organisms or eukaryotic cells, known as bioreactors or fermentors, have been used for production of various biological or chemical products in the pharmaceutical, biotechnological and beverage industry. A typical bioreactor includes a vessel for containing culture medium in a sterile environment that provides the various nutrients required to support growth of the homogeneous biological agents of interest.
Effective cell culture process requires appropriate supplies of nutrient substances, such as glutamine, glucose, and other medium components, and gas, such as oxygen and carbon dioxide, for the growing cells in a bioreactor. In addition, timely control of physiological conditions, such as appropriate pH, temperature, and osmolarity is required for mass cell culture production. In order to provide optimal culture conditions in a bioreactor, rapid and effective mixing in the culture medium is prerequisite, and cells should be uniformly dispersed throughout the culture medium without aggregation in any portion of the cultivation vessel.
During a cell culture process, aseptic withdrawal of a culture broth sample that is representative of the overall cell culture condition is critical for monitoring the performance of the cell culture or fermentation process and for troubleshooting any process problems. The aseptic sampling step is also applicable in medium batching and holding vessels, for which maintaining the desired dissolved carbon dioxide level can be critical to ensuring the proper pH of the cell culture medium. Conventional sample withdrawal from a bioreactor, fermentor, or medium holding vessel, however, is typically performed by a series of manual operations, including purging the sampling line, connecting a sample device aseptically to the line, removing the sample from the bioreactor, and closing the line. The purge step is usually required at the beginning of each sampling step to flush the residual sample in the sampling line from the previous sampling into a waste reservoir. The conventional sample withdrawal procedure results in waste of sample held up in the main sampling line and requires an additional step to switch the sampling line between the waste reservoir and the actual sample container. The conventional sampling procedure also creates the additional step of properly disposing the flushed material.